Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
I have no experience with tunable colort white LEDs, but I've heard they exist.
AFAIK (I'm not 100% sure) it depends on drive current.
Low current generates "warm"light color, and high current generates "cold"light color, similar as with incandescent light bulbs.
Now if you want to tune it you need a DC current source.
PWM does not work. Because it drives the LED with 100% current (when ON) and controls brightness with duty cycle.
--> it generates "cold" light color only.
In my eyes it is not possible to generate "warm" color with high brightness.
To control light color with low brightness:
Warm: 100% duty cycle, 10% current
Cold: 10% duty cycle, 100% current
Warm is rich is yellow (the color temp is actually lower). Cool is rich in blue and has a higher color temp. I have white LEDs and some are warm and some are cool. It uses some phosphor and they look different (without current).
W-filament lamps are always warm; CFL lamps are available in both types- cool and warm. If you are having RGB drive independently then I presume you can tune the proportion of the blue and yellow and produce cool or warm color.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
